hello one and all I am looking for some help with "old " dyes. I have some dye concentrates that I purchase -- oh roughly around 1996 they went hiding :-) and upon moving recently I found them. I am wondering if they are still viable for silk shibori style dyeing? the dyes included:

Sniff the urea. If it smells like ammonia, discard it. Urea breaks down into ammonia, and ammonia can interfere with your dye reactions by altering the pH. If there's no whiff of ammonia, it's okay.

Acid dye can stay good on the shelf for many years. If you can get it to dissolve, go ahead and use it.

The Procion H dyes are similar to Procion MX dyes, but last much longer. After this many years, however, they might be dead. Do a quick test with soda ash on a scrap of fabric; microwave it wet in a ziplock bag if you want a quicker test than properly steaming it (turning the microwave off as soon as the bag billows full of steam).

Like Procion MX dyes, Procion H dyes can be used as acid dyes if you substitute an acid for the sodium carbonate/sodium bicarbonate mixture usually used with it. (Bicarbonate turns into carbonate during the steaming process.) The ability of Procion dyes to act as acid dyes does not go bad, unlike their ability to act as fiber reactive dyes. Fiber reactive dyes used as acid dyes require more acid than most classes of acid dye, and are often less washfast, but many, many dyers have been satisfied with them nonetheless. See my page on "Fiber Reactive Dyes on Protein Fibers".